POLY (METH) ACRYLATES NANOSPHERES OF CENTRALLY ACTING ANALGESIC DRUG FOR POSTOPERATIVE PAIN: IN-VITRO AND IN-VIVO CHARACTERIZATION STUDY

Postoperative pain management is prerequisite element for care of surgical patient. Objective of this study was to develop and evaluate nefopam hydrochloride loaded poly (meth) acrylates nanospheres (NFH-NS) for post-incisional pain treatment. Nefopam hydrochloride (NFH) is a centrally acting, non-opioid analgesic exclusive for treatment of post-incisional pain. NFH-NS were fabricated using eudragit RL 100: RS 100 by quasi solvent diffusion technique to provide sustained release of NFH. Entrapment efficiency (% EE), drug loading (% DL), z-average, polydispersity index and zeta potential (ζ) of NFH-NS was found 84.972 ± 1.23%, 21.41 ± 2.02 %, 648 ± 4.8 nm, 0.53 and + 4.48 mV, respectively. Scanning electron micrographs asserted smooth morphology and substantial spherical shape of nanospheres. In-vitro dissolution test revealed that NFH-NS followed fickian diffusion for drug transport. Mean dissolution time, dissolution efficiency and difference factor (f1) for NFH-NS was 5.68 h, 68.9 % and 31.83, respectively, which indicated dissimilarity in dissolution profiles as compared to NFH. % EE and % DL of NFH-NS at 25 ± 2°C/60 ± 5 % RH and 40 ± 2°C/75 ± 5 % RH revealed stability of formulation. Maximum % reversal of mechanical allodynia was achieved after peroral administration of NFH-NS (30 mg kg^–1) in rat model of post-incisional pain for 14 days. Minimum effective dose (MED) and ED₅₀ of NFH-NS was found 10 mg kg^–1 and 16.4 mg kg^–1, respectively